JP2783246B2 - Active sonar device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active sonar device, and more particularly, to an active sonar device for obtaining external video and Doppler information by using an LFM pulse and a PCW pulse.

[0002]

2. Description of the Related Art In general, there are two types of pulses transmitted and received in an active sonar device: an LFM (Linear Frequency Modulation) pulse for directly changing the frequency and a single frequency PCW (Pulse Continuous Wave) pulse. There is. The LFM pulse is used to display a signal on an active sonar display such as a B-scope because a large gain is obtained by performing cross-correlation processing in reception. On the other hand, the PCW pulse
Used to detect Doppler of the signal.

FIG. 4 is a diagram showing an example of a transmission signal in a conventional active sonar device. FIG. 4A is a diagram showing a transmission beam, and FIG. 4B is a diagram showing a transmission pulse train.

FIG. 4 shows a case where five sets of LFM pulses and PCW pulses are transmitted by an RDT transmission method in which a transmission beam is rotated in time series.

[0005] Here, LFM is applied to one transmission beam.
Because the pulse and the PCW pulse are transmitted in time series,
The total transmission time T ′ is: T ′ = 10τ + 9dτ (τ: pulse width of LFM pulse and PCW pulse, dτ
= Transmission pause time between each pulse).

At the time when a pulse is being transmitted, a pulse reflected outside cannot be received. Therefore, if the sound speed is SV, from 0 to SV / 2 × T
Is a section (short distance blind zone) in which reflected pulses cannot be received.

[0007]

In the conventional active sonar device as described above, the transmission of the LFM pulse and the transmission of the PCW pulse are performed alternately in a time series. This is about twice as large as the case where only the pulse is transmitted, which causes a problem that a section where a reflected pulse cannot be received (a short distance blind zone) becomes large in a short distance. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and it is possible to increase a search range by shortening a transmission time and reducing a short-range blind zone. It is an object of the present invention to provide an active sonar device capable of performing such a method.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for transmitting an LFM pulse and a PCW pulse to receive an externally reflected LFM pulse and a PCW pulse, whereby the LFM pulse and the PCW pulse are reflected. An active sonar device for outputting video and Doppler information of a subject, wherein the LFM pulse and the PC
An adder for adding the W pulse, a transducer for transmitting the LFM pulse and the PCW pulse added in the adder and receiving a pulse reflected outside,
An LFM-based phase adjuster that extracts an LFM pulse from a pulse received by the transducer and performs phasing, and a PCW-based phase adjuster that extracts a PCW pulse from a pulse received by the transducer and performs phasing. And a video processing unit for performing cross-correlation processing of the LFM pulses phased by the LFM phase adjuster and outputting a video signal, and performing FFT processing of the PCW pulses phased by the PCW phase adjuster. And a Doppler processing unit for detecting Doppler of the signal.

An active sonar device for transmitting an LFM pulse and a PCW pulse and receiving an externally reflected LFM pulse and a PCW pulse to output an image and Doppler information of the object reflected by the LFM pulse and the PCW pulse. An adder for adding the LFM pulse and the PCW pulse; a transmitter for transmitting the LFM pulse and the PCW pulse added by the adder; and a pulse output from the transmitter and reflected outside. And an LFM that extracts an LFM pulse from a pulse received by the receiver and performs phasing.
A phase phasing device, a PCW phase phasing device for extracting a PCW pulse from a pulse received by the transducer and phasing,
A cross-correlation process is performed on the LFM pulses phase-aligned in the LFM phase adjuster, and a video processing unit that outputs a video signal, and an FFT process is performed on the PCW pulses phase-aligned in the PCW phase adjuster, A Doppler processing unit that detects Doppler of the signal.

(Operation) In the present invention configured as described above, the LFM pulse and the PCW pulse are added by the adder and transmitted as a composite pulse.

As described above, since the LFM pulse and the PCW pulse are simultaneously transmitted as one pulse for one transmission beam, the total transmission time is reduced, and the short-range blind zone is reduced accordingly. You.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural block diagram showing an embodiment of the active sonar device of the present invention.

In this embodiment, as shown in FIG. 1, an LFM pulse generator 5 for generating an LFM pulse, a PCW pulse generator 6 for generating a PCW pulse, and an LFM pulse generator 5
, A transmission control unit 7 for controlling the output timing of the LFM pulse generated in step 1 and the PCW pulse generated in the PCW pulse generation unit 6, and the LFM pulse output from the LFM pulse generation unit 5 and the output from the PCW pulse generation unit 6. An adder 4 for adding the added PCW pulse, an amplifier 3 for amplifying the pulse added in the adder 4,
A transducer 1 for transmitting a pulse amplified by the amplifier 3 and receiving a pulse reflected outside;
An LFM pulse phasing device 8 that extracts an LFM pulse from a pulse received by the transducer 1 and phasing, and a PCW phasing device that extracts a PCW pulse from a pulse received by the transducer 1 and phasing. A video processing unit 9 for performing cross-correlation processing on the LFM pulses phased by the LFM phase phasing unit 8 and outputting a video signal; and a video processing unit 9
A B-scope display 10 on which the video signal processed in is displayed, and a PC phased by the PCW phaser 8
A Doppler processing unit 12 that performs FFT processing of a W pulse and detects a Doppler of a signal;
2. A Doppler display 13 on which the Doppler signal detected in 2 is displayed, and a pulse amplified by the amplifier 3 is output to the transducer 1, and the pulse received by the transducer 1 is transmitted to the LFM phase adjuster 8 and And a connection box 2 for outputting to the PCW phase adjuster 11.

Hereinafter, the operation of the active sonar device configured as described above will be described.

First, a keying pulse a for controlling the output timing of the LFM pulse generated by the LFM pulse generator 5 and the PCW pulse generated by the PCW pulse generator 6 is output from the transmission controller 7. .

Then, at the timing based on the keying pulse a output from the transmission control unit 7, the LFM
An LFM pulse b having a center frequency f ₁ from the pulse generator 5;
PCW pulse c of frequency f ₂ from PCW pulse generator 6
Are respectively output.

Then, in the adder 4, the LFM pulse b
And the PCW pulse c are added, and the added composite pulse d is sent to the amplifier 3 and amplified.

After that, the pulse amplified by the amplifier 3 is sent to the transmitter / receiver 1 via the connection box 2 and sent to the outside.

When the transmitted pulse is reflected outside, the reflected pulse is received by the transmitter / receiver 1 and is connected via the connection box 2 to the LFM phase adjuster 8 and the PCW phase adjuster 11.
Is output to

Then, in the LFM phase adjuster 8, the LFM of frequency f ₁ is obtained from the pulse output through the connection box 2.
The pulses are extracted, phased, and output to the video processing unit 9.

Further, in the PCW phase adjuster 11, the PCW of frequency f ₂ is obtained from the pulse output through the connection box 2.
The pulses are extracted and phased, and the Doppler system processing unit 12
Is output to

When the phased LFM pulse is input to the video processing unit 9, the cross-correlation processing of the LFM pulse is performed, and the video signal of the target where the LFM pulse is reflected is sent to the B scope display 10. Is displayed.

When the phase-adjusted PCW pulse is input to the Doppler processing unit 12, the FFT of the PCW pulse is performed.
As the processing takes place, the Doppler of the signal is detected,
After that, the Doppler display 13 displays the Doppler signal of the target on which the PCW pulse detected by the Doppler processing unit 12 is reflected.

Hereinafter, the timing of pulse transmission in the above operation will be described in detail.

FIGS. 2A and 2B are diagrams for explaining the timing of pulse transmission in the active sonar device shown in FIG. 1. FIG. 2A shows the timing of a keying pulse a, and FIG. 2B shows the timing of an LFM pulse b. Diagram showing timing,
(C) is a diagram showing the timing of the PCW pulse c, (d)
FIG. 4 is a diagram showing the timing of a composite pulse d.

In this embodiment, five sets of LFM pulses and PCW pulses are transmitted.

As shown in FIG. 2, at the same time as the falling of the keying pulse a, the LFM pulse generator 5
The pulse b and the PCW pulse c are output from the PCW pulse generator 6.

Then, the adder 4 adds the LFM pulse b and the PCW pulse c, and outputs a composite pulse d.

Here, in this embodiment, since the LFM pulse b and the PCW pulse c are simultaneously transmitted as one pulse for one transmission beam, the total transmission time T is T = 5τ + 4dτ (τ: Pulse width of LFM pulse and PCW pulse, dτ
= Transmission pause time between each pulse).

Therefore, the total transmission time is about 1/2 of the total transmission time in the conventional active sonar device,
The short-range blind zone is also reduced to about 1/2.

(Other Embodiments) FIG. 3 is a block diagram showing the configuration of another embodiment of the active sonar device of the present invention.

For the active sonar device shown in FIG. 1 as shown in FIG. 3, a transmitter 101 that specializes in transmitting pulses instead of the transmitter / receiver 1 and a receiver that specializes in receiving pulses are used. In a configuration in which the wave box 102 is provided and the junction box 2 is omitted, the same effect can be obtained if the LFM pulse and the PCW pulse are simultaneously transmitted as one pulse for one transmission beam.

[0035]

As described above, in the present invention,
Since the adder adds the LFM pulse and the PCW pulse to each other and transmits the combined pulse, the LFM pulse and the PCW pulse can be transmitted as one pulse for one transmission beam.

As a result, the total transmission time can be shortened, the short-range blind zone is reduced, the detection area at a short distance is increased, and the search range can be widened.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing one embodiment of an active sonar device of the present invention.

FIG. 2 is a diagram for explaining timing of pulse transmission in the active sonar device shown in FIG. 1;
(A) is a diagram showing the timing of a keying pulse,
(B) is a diagram showing the timing of the LFM pulse, (c) is a diagram showing the timing of the PCW pulse, and (d) is a diagram showing the timing of the composite pulse.

FIG. 3 is a configuration block diagram showing another embodiment of the active sonar device of the present invention.

4A and 4B are diagrams illustrating an example of a transmission signal in a conventional active sonar device, wherein FIG. 4A illustrates a transmission beam, and FIG. 4B illustrates a transmission pulse train.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transducer 2 junction box 3 13 amplifier 4 104 adder 5 105 LFM pulse generator 6 106 PCW pulse generator 7 107 transmission controller 8 108 LFM phase adjuster 9 109 Video processing Unit 10, 110 B-scope display 11, 111 PCW phase adjuster 12, 112 Doppler processing unit 13, 113 Doppler display 101 Transmitter 102 Receiver a Keying pulse b LFM pulse c PCW pulse d Synthetic pulse

Claims (2)

(57) [Claims] An active sonar device for transmitting an LFM pulse and a PCW pulse, receiving an externally reflected LFM pulse and a PCW pulse, and outputting an image and Doppler information of the object on which the LFM pulse and the PCW pulse are reflected. An adder for adding the LFM pulse and the PCW pulse; a transducer for transmitting the LFM pulse and the PCW pulse added by the adder and receiving a pulse reflected outside; and a transducer. An LFM-based phase adjuster that extracts an LFM pulse from a pulse received in the phase shifter, and a PCW pulse that extracts a PCW pulse from a pulse received by the transducer, and performs phase adjustment. Performs cross-correlation processing on the LFM pulses phase-aligned in the system phase adjuster and outputs a video signal A Deo-based processor, the PCW KeiSeisho performs FFT processing phased been PCW pulse in device, active sonar apparatus characterized by having a Doppler system processing unit for detecting the Doppler signal. 2. An active sonar device for transmitting an LFM pulse and a PCW pulse and receiving an externally reflected LFM pulse and a PCW pulse to output an image and Doppler information of the object on which the LFM pulse and the PCW pulse are reflected. An adder for adding the LFM pulse and the PCW pulse; a transmitter for transmitting the LFM pulse and the PCW pulse added by the adder; and a pulse output from the transmitter and reflected outside. A LFM-based phaser for extracting and phasing an LFM pulse from a pulse received by the receiver; and extracting a PCW pulse from a pulse received by the transducer. Performs cross-correlation processing between the phase-shifted PCW phase adjuster and the LFM pulse phased by the LFM phase adjuster. A video processing unit that outputs a video signal; and a Doppler processing unit that performs a FFT process on the PCW pulse phased by the PCW phase adjuster and detects a Doppler of the signal. Sonar device.